Bug 230538 – [IOS 15] Video track does not get unmuted in case of tab was inactive less than ~500 ms

• Status: RESOLVED
• Resolution: FIXED
• Component: WebRTC

Steps:
1. Start video
2. Put to the background and back to foreground right away or switch to a different tab and return

Actual result: Video is not restarted, also visibilitychange event is not fired
Issue is not reproducible on IOS 14.7
Can be tested on WebRTC sample - https://webrtc.github.io/samples/src/content/getusermedia/gum/

[Radar WebKit Bug Importer]

<rdar://problem/83355705>

[Alexey Proskuryakov]

> visibilitychange event is not fired

This seems like it would have an even broader impact.

[youenn fablet]

I can reproduce as well, this seems like a fallout of moving to GPUProcess.
We should probably notify muted state when getting interrupted from GPUProcess, instead of muting the source (which stops the underlying source and ends up removing the possibility to be notified of the unsuspension).

[youenn fablet]

Created attachment 439081 [details]
Patch

[Eric Carlson]

Comment on attachment 439081 [details]
Patch

View in context: https://bugs.webkit.org/attachment.cgi?id=439081&action=review

> Tools/WebKitTestRunner/InjectedBundle/Bindings/TestRunner.idl:386
> +    undefined setMockCameraInterruption(boolean isInterrupted);

Nit: I think the would be better as `setMockCameraIsInterrupted`.

[youenn fablet]

Created attachment 439125 [details]
Patch for landing

[youenn fablet]

Created attachment 439130 [details]
Fix potential test flakiness

[EWS]

Committed r283033 (242093@main): <https://commits.webkit.org/242093@main>

All reviewed patches have been landed. Closing bug and clearing flags on attachment 439130 [details].

[youenn fablet]

*** Bug 230698 has been marked as a duplicate of this bug. ***

[Joel Udwin]

Just tested the repro steps on iOS 15.1 beta 4 and still encountered the issue. Was this expected to be fixed in this release?